The invention relates to a spinning or twisting spindle with a one-piece metal spindle top, comprising a spindle shank and a whirl, said top being connected nonrotatably with a shaft.
It is conventional in modern spindles to make the spindle top of at least two parts, one of which is the spindle shank and the other is the whirl. The spindle shank usually consists of a wrought aluminum alloy. The drive whirl is usually made of steel. Both parts are connected together by the spindle shaft, to which both parts are fixedly connected. The manufacturing cost for such spindles is relatively high, so that these spindles are relatively expensive.
It is also known (French Patent No. 1 016 791) to provide a one-piece spindle top, i.e., to make the spindle shank and the whirl in one piece. It is merely indicated in this patent that this spindle top is to be made of metal or plastic. A spindle of this kind has not found any application in practice. A considerable increase in manufacturing cost would result if this one-piece spindle shank were made entirely of steel, since considerable machining costs would be required. It is not technically feasible to make the spindle top from a wrought aluminum alloy, since this spindle top would then have insufficient abrasion resistance in the vicinity of the whirl.
Thus, an object of the invention is to reduce the manufacturing cost and consequently the price of a spindle of the type described hereinabove. This goal is achieved by virtue of the fact that the spindle top is made in the form of a die-cast part manufactured and of a construction in accordance with the preferred embodiment described below.
This type of manufacture, i.e., die casting, is especially suitable for light spindles, since orders therefor usually reach a sufficiently high number of individual parts, so that the die casting mold does not cause a significant increase in the cost of the workpiece. A choice of material, in accordance with the described embodiments, permits manufacturing spindle tops that have sufficient strength and require only slight additional machining.
In an advantageous embodiment of the invention, the spindle top is made in the form of a die cast part which is slightly oversize relative to its intended final size, and is then machined by copying or profile grinding of its exterior with reference to a pattern part. This ensures that all spindles have exactly the same dimensions and a surface finish of the desired quality is achieved.
In an especially advantageous embodiment of the invention, it is provided that the die cast part is cast over the shaft inserted in the die casting mold. This further simplifies manufacture, since no additional work steps are required to connect the shaft to the spindle top.
It has been found advantageous in practice to make the spindle top of an aluminum alloy. In this connection, it is advantageous for the aluminum alloy to contain more than 12% silicon. This silicon component, which is above the eutectic point, has an especially advantageous effect upon abrasion resistance. The fraction of the silicon which exceeds 12% is not included in the alloy, but occurs in crystalline form, so that it is precisely this fraction which increases abrasion resistance considerably.
These and further objects, features and advantages of the present invention will become more obvious from the following description when taken in connection with the accompanying drawings which show, for purposes of illustration only, several embodiments in accordance with the present invention.